1. The Field of the Invention
The present invention relates to a water powered waste disposal unit with an improved control valve. More particularly, the control valve has a reciprocating control piston disposed in a cylinder with floating seals to prevent leaking and indentations in the piston head or cylinder head to prevent stalling.
2. The Background Art
Waste disposal units disposed under sinks have become commonplace. The waste disposal unit cuts or shreds waste, such as table scraps, so that the waste may pass through pipes of a house plumbing system without clogging the pipes. The disposal units provide the convenience of simply washing waste directly into the sink without having to first wipe the waste into a trash receptacle or having to later clear the waste from a drain in the sink. Disposal units are typically mounted under the sink between the drain in the bottom of the sink and the pipes of the plumbing system and typically have cutters disposed in the units and coupled to electric motors to cut the waste as it passes through the units.
Despite the conveniences provided by these waste disposal units, there are several disadvantages, one of which is the need for electrical wiring to operate the motor. Because of this, the devices are difficult to install and pose a danger of coupling an electric source to the water and plumbing system. Another disadvantage is the low starting torque of the electric motors. Waste initially disposed in the unit may stall the motor. Thus, the motor may burn out or pose a danger of injury as a user reaches into the unit to remove the clogged waste.
U.S. Pat. Nos. 3,700,178, issued Oct. 24, 1972, to Verley, and 4,082,229, issued Apr. 4, 1978, to Boosman, disclose water powered waste disposal units. The units have a housing defining an annular chamber around the unit. A reciprocating drive piston is slidingly disposed in the chamber and is coupled to a pivoting cutter in the housing. A valve alternately directs pressurized water into the annular chamber on opposite sides of the drive piston to drive the piston, and thus the cutter, in a reciprocal rotating motion.
U.S. Pat. No. 4,399,947, issued Aug. 23, 1983, to Spelber et al. discloses a valve for directing the water for a water powered disposal unit. The valve has a reciprocating control piston slidingly disposed in a valve housing. The control piston has a channel formed therein for alternately directing water into the annular chamber on either side of the drive piston as the control piston reciprocates in the valve housing. The valve also has a reciprocating pilot piston slidingly disposed in the housing. The pressure in the annular chamber forces the pilot piston to reciprocate. The pilot piston has a chamber formed therein for alternately directing water to opposite sides of the control piston as the pilot piston reciprocates, thus forcing the control piston to reciprocate.
A detent is disposed in the housing and engages the pilot piston. A spring biases the detent against the pilot piston so that the detent and spring apply an amount of resistance to the pilot piston. The water pressure developed in the annular housing must overcome the amount of resistance applied by the detent to the pilot piston in order to cause the pilot piston to reciprocate.
Despite advantages presented by the above-described water powered waste disposal units, there are also disadvantages. One such disadvantage is the high tolerances required to obtain consistent, efficient performance. Any leaks in the system result in pressure variations which may or may not be sufficient to properly operate the unit. For example, any leaks around the control piston result in water escaping from the control cavity and a loss of pressure at the drive piton. Thus, the unit may be inefficient and inoperable. Another disadvantage is that the control piston tends to stall of stick at the end of its travel. These drawbacks have prevented the substantial advantages of the water powered waste disposal units from being enjoyed.
Therefore, it would be advantageous to develop a water powered waste disposal apparatus, and/or valve for such an apparatus, capable of consistent efficient operation. It would also be advantageous to develop such a disposal apparatus and valve capable of preventing leaks and the resulting loss of pressure. It would also be advantageous to develop such a disposal apparatus and valve capable of preventing stalling, or halted operation.